Three New Coordination Compounds Based on 2‐Phenyl‐4‐quinolinecarboxylic Acid and Nitrogenous Neutral Ligands: Syntheses, Structural Features, and Properties

Solvothermal reactions of 2‐phenyl‐4‐quinolinecarboxylic acid (Hpqba) with Cd II , Co II , Zn II and/or 4,4′‐bipyridyl (4,4′‐bipy), 1,4‐bis(imidazol‐1‐ylmethyl)benzene (biyb), 2,2′‐bipyridyl (2,2′‐bipy) afford three new coordination compounds of stoichiometries [Cd(pqba) 2 (4,4′‐bipy)] ( 1 ), [Zn(pqba) 2 biyb] ( 2 ), and [Co 3 (pqba) 6 ‐(2,2′‐bipy) 2 ] ( 3 ). Compounds 1 – 3 were characterized by elements analysis, IR spectroscopy, thermogravimetry, and single‐crystal X‐ray diffraction study. Compound 1 has a two‐dimensional structure, whereas compound 2 consists of a one‐dimensional (1D) network, which is further expanded by π ··· π stacking interactions to form a 3D supramolecular structure. Complex 3 also exhibits a 3D supramolecular structure completely based on π ··· π stacking interactions. The pqba ligands adopt μ 1 ‐ k 1 , k 1 , μ 1 ‐ k 1 , μ 2 ‐ k 1 , k 1 , and μ 2 ‐ k 1 , k 2 coordination modes for compounds 1 , 2 , and 3 . The fluorescence properties were examined on compounds 1 and 2 in the solid state at room temperature. Magnetic susceptibility measurements indicate that in complex 3 antiferromagnetic coupling between adjacent Co II ions exist.